Litmus tests of the flat $\Lambda$CDM model and model-independent measurement of $H_0r_\mathrm{d}$ with LSST and DESI

TL;DR

This paper presents a model-independent method to test the flat $\\Lambda$CDM model and measure $H_0 r_d$ using simulated LSST and DESI data, constraining cosmological parameters without assuming dark energy models.

Contribution

It introduces an iterative smoothing technique to reconstruct the universe's expansion history from SNIa data combined with BAO measurements, enabling model-independent cosmological tests.

Findings

Can constrain curvature $\Omega_{k,0}$ within ±4%

Can measure $c/(H_0 r_d)$ within ±0.1

Effective in testing flat $\Lambda$CDM with simulated data

Abstract

In this analysis we apply a model-independent framework to test the flat $\Lambda$CDM cosmology using simulated SNIa data from the upcoming Legacy Survey of Space and Time (LSST) and combined with simulated Dark Energy Spectroscopic Instrument (DESI) five-years Baryon Acoustic Oscillations (BAO) data. We adopt an iterative smoothing technique to reconstruct the expansion history from SNIa data, which, when combined with BAO measurements, facilitates a comprehensive test of the Universe's curvature and the nature of dark energy. The analysis is conducted under four different mock true cosmologies: Two curvatures ($\Omega_{k,0}=0$ and 0.1) and two models of dark energy: a cosmological constant $\Lambda$ and the phenomenologically emergent dark energy. We forecast that our reconstruction technique can constrain cosmological parameters, such as the curvature ($\Omega_{k,0}$) and $c/(H_0 r_\mathrm{d})$, with spread due to the SNIa uncertainties up to $\pm 4\%$ and $\pm 0.1$ respectively, without assuming any form of dark energy.